The present invention relates to a mechanism for the selective driving of machines or devices from the power take-off shaft of an agricultural tractor.
It is already known, in agricultural machinery, especially for the driving of movable members of a forage harvester or a similar machine, this term covering pick-up mowing machines, silage makers, etc., to provide a transmission mechanism comprising an input shaft driven from the power take-off shaft of the tractor and two output shafts. One of the output shafts is connected by a suitable transmission to these movable members of the forage harvester, which is most often coupled laterally to the tractor, while the other output shaft may be connected to any device, such as a device provided on a trailer that may be coupled to the tractor. Such a mechanism then merely comprises a set of bevel gears which provide the desired kinematic distribution.
But, in certain countries, the regulations in force forbid the simultaneous driving of a forage harvester and a device provided on a trailer which is coupled to the same tractor as the forage harvester.
With a view to adaptation of these specific regulations, there has therefore been provided for the above-mentioned driving mechanism a single output shaft which provides the drive of the forage harvester, while any possibility of driving the device or devices which are provided on the trailer has been abandoned, or else, there has been fitted on the existing mechanism a stationary cap covering the second output shaft which may normally be connected to the trailer, avoiding, in this second case, a more fundamental modification of the system.
It will nevertheless be understood that this solution, which consists in abandoning the possibility of driving a device other than the forage harvester, itself, from the power take-off shaft of the tractor, represents a handicap to the scheme of work since another motor group must be provided if a device provided on a trailer is to be driven.